I need help, I'm stuck on the whole ratio thing and its winding me up!

ok specs

yokomo dib yokomo 1.8 fcdkawada 80t spur 38dptekin 7.5turn motor

what pinion size should i be running?? last night i ran on a track with a 34t pinion and the motor was getting hot... switched to a 90t spur and it was better but I'm running a 80t for body clearance...

Right now, you're running 3.0fdr. Way too high for 7.5t motor. For your motor and 1.8 rear end, you want to use the biggest spur you can fit on the chassis. 80t is way too small. 7.5t motor should be geared around 7~ 7.5fdr. There's a chart in the manual that shows possible spur/pinion combo to reach that ratio.

Okay I had that problem as well with 13.5! I went with 95t spur 18 combo with the 2.0 set up. Now I'm gonna under drive the front with a 40/14 F and 25/36 R. I seen some guy on youtube with a under driven chassis before with 10 degree castor blocks and it was sliding! Also I'm gonna do the FBD trick with the DIB.